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Remember to give feedback in the Kaiku-system to get the final grade. Seppo Valkealahti
You can answer to the guestions either in English or in Finnish.

53117 Solar Power Systems
Examination, 4.5.2016

Answer to each guestion 1, 2, 3 and 4 should fit into one page of a common writing paper.

a) Tellone concrete measured effect caused by the climatic change during the last 50 to 100 years.

b) When took place the first discoveries of the present photovoltaic (PV) cell?

c) What is the share of Solar PV power of the total installed electricity production capacity
worldwide? = s

d) What has been the average price reduction of PV modules as a function of their installed
cumulative power production capacity?

e) What has been the price development of PV power plant installations during the past 5 to 10
years?

9) What has been the market share of solar PV power plants of the total installed global power
production capacity during the past few years?

a) How does series resistance of PV modules and generator affect to the currents, voltages and
powers of the PV generator?

b) Define the guantity relative air mass number for a PV system location at a mountain top, when a
10 meter high object causes a 5 meter long shadow on a horizontal surface.

e) What are the light absorption processes in direct and indirect band gap PV semiconductors? How
do they effect on needed PV cell thickness?

PV system includes 36 series connected pariauykahardaa ca

identical PV cells. 35 of the cells are under full
irradiance of 1 kW/m? having the green I-V
curve shown in the figure. One of the PV cells
is partially shaded obtaining three different
irradiances of 0, 200 and 600 W/m?. The
corresponding I-V curves are shown in the
figure in the reversed voltage and current
directions with red lines.

b)

Current lin Amps

 

 

Voltage V in Volts

Draw the characteristic 1-V curves of the 36 series connected PV cells, when one cell operates
under those three partial shading conditions and bypass diodes have not been used.

Draw the characteristic I-V curves of the 36. series connected PV cells, when one cell operates
under those three partial shading conditions and three bypass diodes are connected in parallel
with 12 PV cells each.

Imagine that you are selling a PV power system to your customer to be installed on a sloped rooftop
of an existing building. Your customer asks you about the average annual power production of the
system after five years of operation. How do you estimate that (what issues you need to take into
account), when the electrical characteristics of the PV modules are known in standard test
conditions?